CA1189130A - Scanning system for copier - Google Patents
Scanning system for copierInfo
- Publication number
- CA1189130A CA1189130A CA000403985A CA403985A CA1189130A CA 1189130 A CA1189130 A CA 1189130A CA 000403985 A CA000403985 A CA 000403985A CA 403985 A CA403985 A CA 403985A CA 1189130 A CA1189130 A CA 1189130A
- Authority
- CA
- Canada
- Prior art keywords
- lens
- mirror
- angle
- image
- drum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B27/00—Photographic printing apparatus
- G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
- G03B27/52—Details
- G03B27/522—Projection optics
- G03B27/525—Projection optics for slit exposure
- G03B27/526—Projection optics for slit exposure in which the projection optics move
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Lenses (AREA)
- Mechanical Optical Scanning Systems (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
- Optical Systems Of Projection Type Copiers (AREA)
- Facsimile Scanning Arrangements (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An optical system for a copying device is disclosed which scans a document lying in an object plane by means of a pivoting mirror and projects an image of the document onto the surface of a photoreceptor drum. By rotating the projection lens while simultaneously moving an aperture slit in a direction of movement opposite to the movement of the drum, a condition is constantly maintained wherein the object plane, lens plane and image plane are maintained parallel thereby eliminating field tilt. With this configuration, the image is also precessed onto the drum providing a precession distance which can be used to relax constraints normally imposed by scan return conditions.
An optical system for a copying device is disclosed which scans a document lying in an object plane by means of a pivoting mirror and projects an image of the document onto the surface of a photoreceptor drum. By rotating the projection lens while simultaneously moving an aperture slit in a direction of movement opposite to the movement of the drum, a condition is constantly maintained wherein the object plane, lens plane and image plane are maintained parallel thereby eliminating field tilt. With this configuration, the image is also precessed onto the drum providing a precession distance which can be used to relax constraints normally imposed by scan return conditions.
Description
3q:~
SCANNINGSYSTEM FORCOPIF:R
BACKGROUNDANDPRIOR ARTSTATEMENT
This invention relates generally to a xerographic copying devis:e and, more particularly to an optical system which scans a document Iying on 5 an object plane by means of a pivoting mirror and projec~s ~he reflected docurnent image onto a curved photosensitive surface.
Copying devices which u tilize a Eixed ligh-t source ancl pivoting mirror~to scan a document on a curved platen are known in the art, e. g. the ~3~,~ Xerox 2400 and 3600 machines. It is desirable to copy docurnents by placing 10 them on a flat platen while re-taining the scanning simplicity of a pivoting mirror arrangement. Ilowever, this has heretofore not been possihle due to the basic problem of compensating for the "field tilt". Field tilt is the deviation of the image plane frorrl parallelism to the ideal photoreceptor planeduring scan. With use of a flat platen, a keystoning distortion effect also 15 occurs because points on the image plane will vary in focus because of non~
uniform magnification ratio or change in the ratio of the object and image conjugate distances during scan.
In one aspect of the present invention, ~here is provided an optical system which scans a document on a flat platen by means oE a pivoting mirror 20 and projects an image of said document onto a curved phs~toreceptor surface, the imaging being accomplished without the attendant problems of field tilt or keystoning distortion.
According to another feature of the invention~ the scanned image is projected onto a moving photoreceptor at a rate faster than the rate of 25 movement of the photoreceptor and in the direction opposite such movement.
This technique, which can be termed as precessing the image, is generally known in the art. U. S. Patent 3,4549335 (Caldwell) assigned to the same assignee as the present invention, discloses a rnethod oI projecting images on microEilm cards which are moved past a stationary lens and mirror system 30 onto a drum photoreceptor. The drum and microfilm are moved at the same speed but the image is precessed (i.e. moved in a direction opposite the drum motion) onto the drurn surface by means of a slit aperture. This combined slit and drum rotation exposes the drum at a speed (rate) that is greater than the surEace speed of the drum. This scanning system demonstrates two of the ~ de rn~rk advantages gained by lmage precession~ the process speed of the system can be set at A lower speed for equivalent copy rate (copies per rninute) and the gap ordinarily present between images (due to the return time of the scan optics~ can be reduced or eliminated if desired= Scan return velocities for a g1ven copy rate can also be minimized for a given copy rate, thus reducing scan accelerations, forces and vibrations.
problem with such a system, however, is -that defocusing errors may result in developed images unacceptable for some systems. The errors are introduced because the image reflected from the drum mirror to the slit does not maintain perpendicularity to a tangential line at the drum surface.
Thls defocusing problem is addressed in U.SO
4,232,960 (Glab~ assigned to the same assignee as the present invention. Glab solves the problem of field tilt in his particular scan system, by using linear and rotational motions of optical elements located near the drum surface to scan the image onto the drum at the angle corresponding to the angle of reflection of the image from the platen.
Another prior art device which utilizes precession onto a drum photoreceptor is disclosed in U.S. Patent 3,650,621 (Lewis) also assigned to the same assignee as the present inventionO Lewis discloses a system wherein an imaging device is moved in an arcuate path which is in a direction opposite to drum rotation to scan document on a curved platen onto the drum.
Another optical system for precessing an image onto a drum type photoreceptor is disclosed in U.S.
Patent No. 4,373,803 and assigned to the same assignee as the present application. In this patent a dual rate scanning mirror is driven at a speed greater than the process speed of the drum photoreceptor. A drum reflector is adapted to reflect the image onto the drum surface in a direction opposite the drum rotation~
The present invention therefore is further directed to a scanning system which scans a document on ~!
2a a flat platen with a pivoting mirror arrangement while simultaneously precessing an image onto a curved photoreceptor without attendant deEocu~ing problems.
The inventlon is realized in a system which includes a projection lens having an object plane for supporting S an object to be copied; a projection lens having a rotational and translational motion; a pivo-ting mirror for scanning said object and reflecting said light image towards said projection lens; an aperture sLit located adjacent the ~\!
curvilinear surface, the aperture sli t rnoving in a direc-tion opposi te the direc-tion of movemen-t of the curvilinear surface; means for main-tainin~
constant conjugate during scan; and means for synchronizing the mo-tions of said lens, mirror and aperture slit so as to main-tain parallel object, lens and5 image planes during the entire scan cycle; whereby said lens rota~es simultan-eously with said reflector and slit motion to continually maintain said projected image at the pho-tosensitive su~face at the sarne angle of inciclerlceas the angle of the principal scanning ray at -the object plane.
DRAWII``l(:lS
10Figure I is a simplified scllematic of a straight through scan system illustrating the principles oE the present inverrtion.
Figure 2 shows the angular rela tionship o-f scan mirror line and imaging slit for an objec-t segment.
Figure 3 illustrates the enabling field tilt free condition wherein 15 object, line and image planes are arranged in parallel relationship during any portion of scan.
Figure 4 is an embodiment of the scanning system of the present invention .
DESCRIPTION
20In a pivoting mirror optical system which scans a document to be reproduced, the main requirement is to main-tain an angle of incidence of the principal ray reflected from a document placed on an object plane equal to the angle of incidence of the ray at a photosensitive imaging plane while maintaining the total optical conjugate. One way of accomplishing this is to 25introduce a curvature to the object plane9 e. g. a document platen, as is the ~;case for example with the Xerox 2400 and 7000 machines. If a flat docurnent -platen is to be used, the virtual image of a scanned point moves out of the plane of the platen resulting in tilted imaging on the curved pho-toreceptor.
This condition9 and an optical system which compensates for i-t, is shown in 30Figures I and 2. These figures, for purpose of clarityJ show an unfolded optical system and ignore, for the moment, the conjugate corrections~
Referring now to Figure 1, a document 10 is located on platen 12.
Pivoting mirror 14 rotates through some angle as to scan the document from segments A through B, C. During the scan cycle the ver-tical images oE the 35scanned segments are moved out of the objec-t plane to the indicated A', C' locations, and, if lens 16 were fixed, the irnaging would be out oE -the lens plane ~r~ rk and tilted to i-t by some angle. Ignoring for a moment the change in object to lens conjuga-te, the problem addressed in the figure is the elimination of this field tilt of -the images A", C" at the photoreceptor drum 18. Applicant has perceived that if, during the scan cycle, the object plane, lens plane (plane 5 perpendicular to lens axis) and image plane were maintained in a parallel relationship ~while simultaneously maintaining total conjugate) field tilt wouklbe eliminated. This has been accomplished by displacing an aperture slit 20 at some angle relative to the lens and in a direction opposite the drum movement.
Figure 2 shows the conditions necessary to e.liminate field tilt for the imaging of scanned segment A. Referring -to this figure, rnirror 14 is rotatecl on angle ~ /2 causing the virtual image of area A to move to A'. The image is now out of the plane of lens 16, which is normally parallel to platen 12 and tilted to it by an angle y~ . Simultaneously with the movement of mirror 15 14, however, lens 16 is tilted by angle Y' and aperture slit 20 is at a position where it forms an angle ~ relative to centerline 22. The angle ~ is selected such that an angle ~t) is subtended on the drum. The actual angle subtended by A' is Q ( ~ -~ ) and, the object plane 30, lens plane 32 and image plane 34 are parallel as shown in Fi~ure 3. During an entire scan operation, as shown in 20 Figure 1, mirror 14 rotates through an angle ~ ~ . Simultaneously, slit 20 moves in a direction opposite the drum rotation to cause a displacement ~ ~
relative to lens 16 and is incidently the angle 'Y at tne drum. The motion of lens 16 is synchroni~ed with tllat of mirror 14 and slit 20 to rotate an angle ~1~
to maintain parallel object and image planes. After cornpletion of the scan 25 cycle, the image of segment C is at C". By advancing the slit 20 in the direction opposite the drum rotation, the projected image has been precessed along the drum surface imparting an incidental but important characteristic to this system. The time taken for drum 18 to move to the start of scan position A" can be used to beneicially alter the rescan velocities of the scan 30 components, ease system process speeds and reduce or eliminate inter-document gap, thereby enhancing system throughput.
Referring now to Figure 4, there is shown an embodiment of the present invention which accomplishes a field-tilt-free scan of a document on a 1at platen using the principles described above and adding additional elements 35 to rnaintain total conjugate. In Figure 4, document 10, Iying on platen 12 isscanned by mirror 14. An illumina tion source9 no t shown, illurninates the underside oE the platen. As in Figure 1, lens 16 projects -the scanned image through moving slit 20 onto photoreceptor drum 20. The basic operation is as described above; the rotation of lens 16 is synchronized with the ro-tation of mirror 14 (relatiYe to the optical axis~ and the movement of slit 20 to maintain5 parallel object, lens and irnage planes to eliminate Eield til-t. During the scan cycle5 however, -the object-to-lens distance is changing due to two factors, theobject to mirror distance L changing by L cos ~ and the ro-tation of the 1ens causes an incremental change in the anguJar path of the prlncipal ray. Since lens 16, in this embodirnent, has a fixed focal length, the above changes must 10 be compensated for so as to maintain the total conjugate and Iceep the projected image in proper focus. This compensation is provided by adding mirror 40 which moves in the direction shown in conjunc-tion wi-th a displace-ment of mirror 14 while lens 16 is simultaneously rotating and translating alongthe optical axis.
While the invention has been described in the context of a preferred embodiment, other modifica-tions are possible consistent with the spirit of the invention. For example, a zoom lens may be used in place of the fixed focal length lens. In this case, mirror 40 would not be required.
Examples of zoom lenses are known in the art; e. g. as disclosed in U. S. Patents 20 3,901,585, 49056,3087 and 4J076~388.
SCANNINGSYSTEM FORCOPIF:R
BACKGROUNDANDPRIOR ARTSTATEMENT
This invention relates generally to a xerographic copying devis:e and, more particularly to an optical system which scans a document Iying on 5 an object plane by means of a pivoting mirror and projec~s ~he reflected docurnent image onto a curved photosensitive surface.
Copying devices which u tilize a Eixed ligh-t source ancl pivoting mirror~to scan a document on a curved platen are known in the art, e. g. the ~3~,~ Xerox 2400 and 3600 machines. It is desirable to copy docurnents by placing 10 them on a flat platen while re-taining the scanning simplicity of a pivoting mirror arrangement. Ilowever, this has heretofore not been possihle due to the basic problem of compensating for the "field tilt". Field tilt is the deviation of the image plane frorrl parallelism to the ideal photoreceptor planeduring scan. With use of a flat platen, a keystoning distortion effect also 15 occurs because points on the image plane will vary in focus because of non~
uniform magnification ratio or change in the ratio of the object and image conjugate distances during scan.
In one aspect of the present invention, ~here is provided an optical system which scans a document on a flat platen by means oE a pivoting mirror 20 and projects an image of said document onto a curved phs~toreceptor surface, the imaging being accomplished without the attendant problems of field tilt or keystoning distortion.
According to another feature of the invention~ the scanned image is projected onto a moving photoreceptor at a rate faster than the rate of 25 movement of the photoreceptor and in the direction opposite such movement.
This technique, which can be termed as precessing the image, is generally known in the art. U. S. Patent 3,4549335 (Caldwell) assigned to the same assignee as the present invention, discloses a rnethod oI projecting images on microEilm cards which are moved past a stationary lens and mirror system 30 onto a drum photoreceptor. The drum and microfilm are moved at the same speed but the image is precessed (i.e. moved in a direction opposite the drum motion) onto the drurn surface by means of a slit aperture. This combined slit and drum rotation exposes the drum at a speed (rate) that is greater than the surEace speed of the drum. This scanning system demonstrates two of the ~ de rn~rk advantages gained by lmage precession~ the process speed of the system can be set at A lower speed for equivalent copy rate (copies per rninute) and the gap ordinarily present between images (due to the return time of the scan optics~ can be reduced or eliminated if desired= Scan return velocities for a g1ven copy rate can also be minimized for a given copy rate, thus reducing scan accelerations, forces and vibrations.
problem with such a system, however, is -that defocusing errors may result in developed images unacceptable for some systems. The errors are introduced because the image reflected from the drum mirror to the slit does not maintain perpendicularity to a tangential line at the drum surface.
Thls defocusing problem is addressed in U.SO
4,232,960 (Glab~ assigned to the same assignee as the present invention. Glab solves the problem of field tilt in his particular scan system, by using linear and rotational motions of optical elements located near the drum surface to scan the image onto the drum at the angle corresponding to the angle of reflection of the image from the platen.
Another prior art device which utilizes precession onto a drum photoreceptor is disclosed in U.S. Patent 3,650,621 (Lewis) also assigned to the same assignee as the present inventionO Lewis discloses a system wherein an imaging device is moved in an arcuate path which is in a direction opposite to drum rotation to scan document on a curved platen onto the drum.
Another optical system for precessing an image onto a drum type photoreceptor is disclosed in U.S.
Patent No. 4,373,803 and assigned to the same assignee as the present application. In this patent a dual rate scanning mirror is driven at a speed greater than the process speed of the drum photoreceptor. A drum reflector is adapted to reflect the image onto the drum surface in a direction opposite the drum rotation~
The present invention therefore is further directed to a scanning system which scans a document on ~!
2a a flat platen with a pivoting mirror arrangement while simultaneously precessing an image onto a curved photoreceptor without attendant deEocu~ing problems.
The inventlon is realized in a system which includes a projection lens having an object plane for supporting S an object to be copied; a projection lens having a rotational and translational motion; a pivo-ting mirror for scanning said object and reflecting said light image towards said projection lens; an aperture sLit located adjacent the ~\!
curvilinear surface, the aperture sli t rnoving in a direc-tion opposi te the direc-tion of movemen-t of the curvilinear surface; means for main-tainin~
constant conjugate during scan; and means for synchronizing the mo-tions of said lens, mirror and aperture slit so as to main-tain parallel object, lens and5 image planes during the entire scan cycle; whereby said lens rota~es simultan-eously with said reflector and slit motion to continually maintain said projected image at the pho-tosensitive su~face at the sarne angle of inciclerlceas the angle of the principal scanning ray at -the object plane.
DRAWII``l(:lS
10Figure I is a simplified scllematic of a straight through scan system illustrating the principles oE the present inverrtion.
Figure 2 shows the angular rela tionship o-f scan mirror line and imaging slit for an objec-t segment.
Figure 3 illustrates the enabling field tilt free condition wherein 15 object, line and image planes are arranged in parallel relationship during any portion of scan.
Figure 4 is an embodiment of the scanning system of the present invention .
DESCRIPTION
20In a pivoting mirror optical system which scans a document to be reproduced, the main requirement is to main-tain an angle of incidence of the principal ray reflected from a document placed on an object plane equal to the angle of incidence of the ray at a photosensitive imaging plane while maintaining the total optical conjugate. One way of accomplishing this is to 25introduce a curvature to the object plane9 e. g. a document platen, as is the ~;case for example with the Xerox 2400 and 7000 machines. If a flat docurnent -platen is to be used, the virtual image of a scanned point moves out of the plane of the platen resulting in tilted imaging on the curved pho-toreceptor.
This condition9 and an optical system which compensates for i-t, is shown in 30Figures I and 2. These figures, for purpose of clarityJ show an unfolded optical system and ignore, for the moment, the conjugate corrections~
Referring now to Figure 1, a document 10 is located on platen 12.
Pivoting mirror 14 rotates through some angle as to scan the document from segments A through B, C. During the scan cycle the ver-tical images oE the 35scanned segments are moved out of the objec-t plane to the indicated A', C' locations, and, if lens 16 were fixed, the irnaging would be out oE -the lens plane ~r~ rk and tilted to i-t by some angle. Ignoring for a moment the change in object to lens conjuga-te, the problem addressed in the figure is the elimination of this field tilt of -the images A", C" at the photoreceptor drum 18. Applicant has perceived that if, during the scan cycle, the object plane, lens plane (plane 5 perpendicular to lens axis) and image plane were maintained in a parallel relationship ~while simultaneously maintaining total conjugate) field tilt wouklbe eliminated. This has been accomplished by displacing an aperture slit 20 at some angle relative to the lens and in a direction opposite the drum movement.
Figure 2 shows the conditions necessary to e.liminate field tilt for the imaging of scanned segment A. Referring -to this figure, rnirror 14 is rotatecl on angle ~ /2 causing the virtual image of area A to move to A'. The image is now out of the plane of lens 16, which is normally parallel to platen 12 and tilted to it by an angle y~ . Simultaneously with the movement of mirror 15 14, however, lens 16 is tilted by angle Y' and aperture slit 20 is at a position where it forms an angle ~ relative to centerline 22. The angle ~ is selected such that an angle ~t) is subtended on the drum. The actual angle subtended by A' is Q ( ~ -~ ) and, the object plane 30, lens plane 32 and image plane 34 are parallel as shown in Fi~ure 3. During an entire scan operation, as shown in 20 Figure 1, mirror 14 rotates through an angle ~ ~ . Simultaneously, slit 20 moves in a direction opposite the drum rotation to cause a displacement ~ ~
relative to lens 16 and is incidently the angle 'Y at tne drum. The motion of lens 16 is synchroni~ed with tllat of mirror 14 and slit 20 to rotate an angle ~1~
to maintain parallel object and image planes. After cornpletion of the scan 25 cycle, the image of segment C is at C". By advancing the slit 20 in the direction opposite the drum rotation, the projected image has been precessed along the drum surface imparting an incidental but important characteristic to this system. The time taken for drum 18 to move to the start of scan position A" can be used to beneicially alter the rescan velocities of the scan 30 components, ease system process speeds and reduce or eliminate inter-document gap, thereby enhancing system throughput.
Referring now to Figure 4, there is shown an embodiment of the present invention which accomplishes a field-tilt-free scan of a document on a 1at platen using the principles described above and adding additional elements 35 to rnaintain total conjugate. In Figure 4, document 10, Iying on platen 12 isscanned by mirror 14. An illumina tion source9 no t shown, illurninates the underside oE the platen. As in Figure 1, lens 16 projects -the scanned image through moving slit 20 onto photoreceptor drum 20. The basic operation is as described above; the rotation of lens 16 is synchronized with the ro-tation of mirror 14 (relatiYe to the optical axis~ and the movement of slit 20 to maintain5 parallel object, lens and irnage planes to eliminate Eield til-t. During the scan cycle5 however, -the object-to-lens distance is changing due to two factors, theobject to mirror distance L changing by L cos ~ and the ro-tation of the 1ens causes an incremental change in the anguJar path of the prlncipal ray. Since lens 16, in this embodirnent, has a fixed focal length, the above changes must 10 be compensated for so as to maintain the total conjugate and Iceep the projected image in proper focus. This compensation is provided by adding mirror 40 which moves in the direction shown in conjunc-tion wi-th a displace-ment of mirror 14 while lens 16 is simultaneously rotating and translating alongthe optical axis.
While the invention has been described in the context of a preferred embodiment, other modifica-tions are possible consistent with the spirit of the invention. For example, a zoom lens may be used in place of the fixed focal length lens. In this case, mirror 40 would not be required.
Examples of zoom lenses are known in the art; e. g. as disclosed in U. S. Patents 20 3,901,585, 49056,3087 and 4J076~388.
Claims (4)
1. A scanning system for projecting light images of a stationary object along an optical path onto a curvilinear photosensitive surface comprising:
an object plane for supporting an object to be copied;
a projection lens having a rotational and translational motion;
a pivoting mirror for scanning said object and reflecting said light image towards said projection lens;
an aperture slit located adjacent the curvilinear surface, the aperture slit moving in a direction opposite the direction of movement o-f the curvilinear surface;
means for maintaining constant conjugate during scan; and means for synchronizing the motions of said lens, mirror and aperture slit so as to maintain parallel object lens and image planes during the entire scan cycle;
whereby said lens rotates simultaneously with said reflector and slit motion to continually maintain said projected image at the photosensitive surface at the same angle of incidence as the angle of the principal scanning ray at the object plane.
an object plane for supporting an object to be copied;
a projection lens having a rotational and translational motion;
a pivoting mirror for scanning said object and reflecting said light image towards said projection lens;
an aperture slit located adjacent the curvilinear surface, the aperture slit moving in a direction opposite the direction of movement o-f the curvilinear surface;
means for maintaining constant conjugate during scan; and means for synchronizing the motions of said lens, mirror and aperture slit so as to maintain parallel object lens and image planes during the entire scan cycle;
whereby said lens rotates simultaneously with said reflector and slit motion to continually maintain said projected image at the photosensitive surface at the same angle of incidence as the angle of the principal scanning ray at the object plane.
2. The scanning system of claim 1 wherein said rotatable mirror and said lens scar through an angle ??, and said aperture slit rotates through an angle ?.alpha. relative to said lens so as to cause any angle ?? to be subtended at the photosensitive surface.
3. The scanning system of claim 1 further including a second translatable mirror located along the optical path between said rotatable mirror and said lens, said second mirror cooperating with a translation of said rotatable mirror to maintain total conjugate during scan.
4. The scanning system of claim 1 wherein said projection lens is a zoom-type lens.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/269,522 US4367034A (en) | 1981-06-01 | 1981-06-01 | Scanning system for copier |
| US269,522 | 1988-11-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189130A true CA1189130A (en) | 1985-06-18 |
Family
ID=23027632
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000403985A Expired CA1189130A (en) | 1981-06-01 | 1982-05-28 | Scanning system for copier |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US4367034A (en) |
| JP (1) | JPS57204067A (en) |
| CA (1) | CA1189130A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63115124A (en) * | 1986-11-04 | 1988-05-19 | Canon Inc | Scanning device |
| JP5218049B2 (en) * | 2006-05-31 | 2013-06-26 | 株式会社ニコン | Exposure apparatus and exposure method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3454335A (en) * | 1966-12-30 | 1969-07-08 | Xerox Corp | Scanning system |
| US3650621A (en) * | 1969-03-28 | 1972-03-21 | Xerox Corp | Optical imaging system |
| US3901585A (en) * | 1973-10-23 | 1975-08-26 | Xerox Corp | Zoom lens assembly |
| US4076388A (en) * | 1974-10-21 | 1978-02-28 | Xerox Corporation | Zoom lens assembly |
| US4056308A (en) * | 1976-03-03 | 1977-11-01 | Xerox Corporation | Variable focal length reflector lens system |
| US4232960A (en) * | 1979-02-21 | 1980-11-11 | Xerox Corporation | Scanning system |
-
1981
- 1981-06-01 US US06/269,522 patent/US4367034A/en not_active Expired - Lifetime
-
1982
- 1982-05-24 JP JP57087833A patent/JPS57204067A/en active Pending
- 1982-05-28 CA CA000403985A patent/CA1189130A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57204067A (en) | 1982-12-14 |
| US4367034A (en) | 1983-01-04 |
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